Cassola-Roth consort collection
Music for viols and more. Mostly polyphonic music in practical editions, with separated parts.
In ChoralWiki, the Choral Public Domain Library, you will find free choral/vocal scores, texts, translations, and other information.
International Music Score Library Project (IMSLP)
The International Music Score Library Project (Petrucci Music Library) provide music scores free of charge. Many facsimiles are included.
A collection of modern editions dedicated to Renaissance and Baroque music scores, with an accent on music for (or suitable to) viola da gamba or viola da gamba consort.